Messages in this thread | | | Date | Sat, 16 May 2009 22:55:58 +0200 | From | Luca Tettamanti <> | Subject | Re: [2.6.30-rc6] cifs_close: NULL pointer dereference |
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On Sat, May 16, 2009 at 06:28:13PM +0200, Luca Tettamanti wrote: > Hello, > I just hit a NULL pointer dereference in cifs_close while accessing a file on a > remote Samba shared directory. [...] > BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > IP: [<ffffffffa05f105c>] cifs_close+0x1c1/0x2e8 [cifs]
Ok, I've reproduced this on a machine with a serial port :)
0xffffffff803574e0 in list_del (entry=0xffff8800ac184210) at /home/kronos/src/linux-2.6.git/lib/list_debug.c:46 46 WARN(entry->prev->next != entry, (gdb) bt #0 0xffffffff803574e0 in list_del (entry=0xffff8800ac184210) at /home/kronos/src/linux-2.6.git/lib/list_debug.c:46 #1 0xffffffff80319588 in cifs_close (inode=0xffff8800b8d5f088, file=0xffff8800ad8f6d00) at /home/kronos/src/linux-2.6.git/fs/cifs/file.c:670 #2 0xffffffff8029d95e in __fput (file=0xffff8800ad8f6d00) at /home/kronos/src/linux-2.6.git/fs/file_table.c:281 #3 0xffffffff8029da32 in fput (file=0xffff8800ac184210) at /home/kronos/src/linux-2.6.git/fs/file_table.c:227 #4 0xffffffff8029ad30 in filp_close (filp=0xffff8800ad8f6d00, id=0xffff880037a3e080) at /home/kronos/src/linux-2.6.git/fs/open.c:1108 #5 0xffffffff8029ade0 in sys_close (fd=0) at /home/kronos/src/linux-2.6.git/fs/open.c:1137 #6 0xffffffff802271e4 in sysenter_dispatch () at /home/kronos/src/linux-2.6.git/arch/x86/ia32/ia32entry.S:161 #7 0x0000000000000000 in ?? ()
(gdb) f 1 #1 0xffffffff80319588 in cifs_close (inode=0xffff8800b8d5f088, file=0xffff8800ad8f6d00) at /home/kronos/src/linux-2.6.git/fs/cifs/file.c:670 670 list_del(&pSMBFile->flist);
(gdb) p *&pSMBFile->flist $2 = {next = 0x0, prev = 0x0}
(gdb) p *&pSMBFile->tlist $5 = {next = 0x0, prev = 0x0}
So both flist and tlist were not initilized in cifs_open.
The content of the whole pSMBFile structure:
(gdb) p *pSMBFile $6 = {tlist = {next = 0x0, prev = 0x0}, flist = {next = 0x0, prev = 0x0}, uid = 0, pid = 5322, netfid = 13880, pfile = 0xffff8800ad8f6d00, pInode = 0xffff8800b8d5f088, lock_mutex = {count = {counter = 1}, wait_lock = {raw_lock = { slock = 514}, magic = 3735899821, owner_cpu = 4294967295, owner = 0xffffffffffffffff, dep_map = { key = 0xffffffff806a5c98, class_cache = 0x0, name = 0xffffffff80537308 "&lock->wait_lock"}}, wait_list = { next = 0xffff8800ac184278, prev = 0xffff8800ac184278}, owner = 0x0, name = 0x0, magic = 0xffff8800ac184240, dep_map = { key = 0xffffffff80d7ff50, class_cache = 0xffffffff80835400, name = 0xffffffff8054cdfa "&private_data->lock_mutex"}}, llist = {next = 0xffff8800ac1842b8, prev = 0xffff8800ac1842b8}, closePend = true, invalidHandle = false, messageMode = false, wrtPending = {counter = 0}, fh_mutex = {count = {counter = 1}, wait_lock = {raw_lock = {slock = 0}, magic = 3735899821, owner_cpu = 4294967295, owner = 0xffffffffffffffff, dep_map = {key = 0xffffffff806a5c98, class_cache = 0x0, name = 0xffffffff80537308 "&lock->wait_lock"}}, wait_list = {next = 0xffff8800ac184308, prev = 0xffff8800ac184308}, owner = 0x0, name = 0x0, magic = 0xffff8800ac1842d0, dep_map = {key = 0xffffffff80d7ff58, class_cache = 0x0, name = 0xffffffff8054cde2 "&private_data->fh_mutex"}}, srch_inf = {index_of_last_entry = 0, entries_in_buffer = 0, info_level = 0, resume_key = 0, ntwrk_buf_start = 0x0, srch_entries_start = 0x0, last_entry = 0x0, presume_name = 0x0, resume_name_len = 0, endOfSearch = false, emptyDir = false, unicode = false, smallBuf = false}}
Luca
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